Phytochrome A regulates the intracellular distribution of phototropin 1-green fluorescent protein in Arabidopsis thaliana.
It has been known for decades that red light pretreatment has complex effects on subsequent phototropic sensitivity of etiolated seedlings. Here, we demonstrate that brief pulses of red light given 2 h prior to phototropic induction by low fluence rates of blue light prevent the blue light-induced loss of green fluorescent protein-tagged phototropin 1 (PHOT1-GFP) from the plasma membrane of cortical cells of transgenic seedlings of Arabidopsis thaliana expressing PHOT1-GFP in a phot1-5 null mutant background. This red light effect is mediated by phytochrome A and requires approximately 2 h in the dark at room temperature to go to completion. It is fully far red reversible and shows escape from photoreversibility following 30 min of subsequent darkness. Red light-induced inhibition of blue light-inducible changes in the subcellular distribution of PHOT1-GFP is only observed in rapidly elongating regions of the hypocotyl. It is absent in hook tissues and in mature cells below the elongation zone. We hypothesize that red light-induced retention of the PHOT1-GFP on the plasma membrane may account for the red light-induced increase in phototropic sensitivity to low fluence rates of blue light.
Han
In-Seob
IS
Department of Biological Sciences, University of Ulsan, Ulsan 680-749, Korea.
Tseng
Tong-Seung
TS
Eisinger
William
W
Briggs
Winslow R
WR
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000032:analysis / Q000378:metabolism* / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000032:analysis; D008027:Light; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism*; D051942:Phytochrome A / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000378:metabolism / Q000528:radiation effects; D017346:Protein Serine-Threonine Kinases; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000032:analysis
D029681:Arabidopsis Proteins; C497973:PHYA protein, Arabidopsis; D010750:Phosphoproteins; D051942:Phytochrome A; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases